7 replies to this topic

[dummyad]

Hello!
 

I am using Aspen Hysys to design a process for air liquefaction.

I want to implement Claude-process but for simplicity I started with a Linde-cycle.

 

Since I am originally an electrical engineer I am not used to this software at all and have a few questions.

 

So far along the air stream I have defined temperature and/or pressure values front of or after the different components, the software calculated the unknown parameters.

In static analysis this seems to work fine. (see attachment)

In dynamic analysis, I get this error: "LNG operation pressure flow" and I have no idea to change it. (avoided any pressure drops)

 

My aim is to get the geometric parameters for developing a simple double-pipe (counterflow) heat exchanger based on the thermodynamic parameters the software has calculated and the material (copper) I want to use (and maybe one pipe diameter would be defined by me).

 

Questions:

Is this possible and if so, what is the best way to do that?

Is the LNG-component the right form of heat exchanger I am using (how can I simulate the double-pipe heat exchanger case?)

 

General question: Does the dynamic analysis (which does not work yet, since I have the error above) offer me the possibility to simulate this process outgoing from room temperature (for all components) - which should be the practical case when driving up the process. - basically I would need a transient analysis.

How can I do that?

 

Thanks in advance!

Attached Files

•  aspen.PNG   31.29KB   3 downloads

[Bobby Strain]

Best you call for experienced help in your organization.

 

Bobby

[dummyad]

OK, the problem is, that this is a DIY-project and not organization-related.

 

That's why I chose to write into this forum to get help.

[dummyad]

Has none of you (the viewers) designed a heat exchanger based on process parameters?

 

I have found a tool called "Aspen Heat Exchanger Design and Rating" where it is possible to import Aspen Hysys heat exchanger parameters.

Selected TEMA-type: BDM (D stands for D-shell [Double pipe])

But the problem seems to be that no matter what type I select, all types of "Shell and tube heat exchangers" are using several tubes or several shells in the result.

[A summary is in the attachment! (tube diameter: 6mm; unit diameter: 57mm !!!!)]

 

If someone can tell me trick how I can design a SIMPLE double-pipe-type heat exchanger it would be nice, or maybe this is impossible with this software?

 

Apart from that there is still the problem with the dynamic simulation - if somebody can give a hint I would appreciate that. (transient analysis...)

Attached Files

•  aspen_HE.PNG   28.21KB   2 downloads

Edited by dummyad, 26 September 2014 - 06:29 PM.

[srfish]

Why ar you using Double Pipe heat heat exchangers ? Connecting all of those 16 units would require a lot of extra piping.

[dummyad]

Hello srfish,

 

I want to build such a heat exchanger on my own.

 

Therefore it should be cheap and simple and (based on what I know) the easiest counterflow-heat exchanger is a double-pipe heat exchanger. If someone has a better idea, feel free to tell me.

 

The Linde-cycle and it's heat exchanger I am currently using is just a simulation test-cycle since it is easier than Claude-cycle, and I hope that for Claude-cycle the three or maybe two heat exchangers will not have such extreme dimensions (hopefully).

[farnaz sanandaji]

Hi Dummyad

 

Please attach native Aspen file. after reviewing your native file I will help you. 

[dummyad]

Hi farnaz,

 

I have attached the files for Linde and Claude-cycle.

 

In both files I have the same problem with the dynamic simulation ("LNG operation pressure flow"), in Claude-cycle I have an additional problem with "temperature cross".

Attached Files

•  linde_claude.zip   187.49KB   65 downloads

Edited by dummyad, 18 October 2014 - 01:00 PM.